Making Change

PROCEDURE. Ask the following questions in the order here given:--

(a) "_If I were to buy 4 cents worth of candy and should give
the storekeeper 10 cents, how much money would I get back?_"
(b) "_If I bought 13 cents worth and gave the storekeeper
15 cents, how much would I get back?_"
(c) "_If I bought 4 cents worth and gave the storekeeper
25 cents, how much would I get back?_"

Coins are not used, and the subject is not allowed the help of pencil
and paper. If the subject forgets the statement of the problem, it is
permissible to repeat it once, but only once. The response should be
made in ten or fifteen seconds for each problem.

SCORING, The test is passed if _two out of three_ problems are answered
correctly in the allotted time. In case two answers are given to a
problem, we follow the usual rule of counting the second and ignoring
the first.

REMARKS. Problems of this nature, when thoroughly standardized, are
extremely valuable as tests of intelligence. The difficulty of the test,
as we have used it, does not lie in the subtraction of 4 from 10, 12
from 15, etc. Such subtractions, when given as problems in subtraction,
are readily solved by practically all normal 8-year-olds who have
attended school as much as two years. The problems of the test have a
twofold difficulty: (1) The statement of the problem must be
comprehended and held in mind until the solution has been arrived at;
(2) the problem is so stated that the subject must himself select the
fundamental operation which applies. The latter difficulty is somewhat
the greater of the two, addition sometimes being employed instead of
subtraction.

It is just such difficulties as this that prove so perplexing to the
feeble-minded. High-grade defectives, although they require more than
the usual amount of drill and are likely to make occasional errors, are
nevertheless capable of learning to add, subtract, multiply, and divide
fairly well. Their main trouble comes in deciding which of these
operations a given problem calls for. They can master routine, but as
regards initiative, judgment, and power to reason they are little
educable. The psychology and pedagogy of mental deficiency is epitomized
in this statement.

There has been little disagreement as to the proper location of the test
of making change, but various procedures have been employed. Coins have
generally been employed, in which case the subject is actually allowed
to make the change. Most other revisions have also given only a single
problem, usually 4 cents out of 20 cents, or 4 out of 25, or 9 out of
25. It is evident that these are not all of equal difficulty. There is
general agreement, however, that normal children of 9 years should be
able to make simple change.